Thank you Penguin for this ARC
Tense, mysterious, and queer, The Narrow is must read horror novel that will leave you gasping for air.
We follow Eden, returning to her boarding school and discovering that her parents chose not to pay her tuition. (Key word: chose!) Her only option is a scholarship by way of being a companion to the mysterious Delphine, a student confined to her quarters because of her mysterious illness.  The house that is odd, locks all over the doors, cameras and one very important rule. Don't let the water in. 
I will never get tired of reading horror books that have to do with water and drowning. Like bread and butter, it just goes together so well.
It took me a second to get into the story, but once I got past the beginning I found it very thrilling and and full of suspense. We are given enough breadcrumbs and clues to kind of piece together the mystery, but there were still still so many twists and turns that kept me on my toes.
I really interpreted a lot of the story to be symbolism for abusive relationships. Eden is so constantly making excuses for other people and her family. Even with the support of her friends she still falls into a bad situation, and seems to think she deserves it, and they aren't meaning her harm. She ends up very isolated and alone, and even gets to the point of failing her classes. Eden is so intent on hiding the pain she is in that it takes a good chunk of the book for her to even go to the hospital and get a splint for her arm. (Also the tooth scene creeped me out...gross!)
Queer horror is a genre that I have been dipping my toe in lately, and this book does it so well. Not only is Eden queer and we some lovely sapphic romance, but it is a core component of the whole plot. Whether it be homophobia, or presuming what you know about strangers, it really pulled the rug out from under me. When the reveal happened at the end, I COULD NOT HANDLE IT! I had to facetime my friend and freak out because I was so shocked!
One of the aspects I found most enjoyable was the friendship group that Eden had. It is always so refreshing to healthy and supportive friendships, and I loved how they were trying so hard to be there for Eden. There was a very beautiful quote that Veronica tells to her that really stuck with me: "You fall in love with all your friends. It's kind of a beautiful thing about you." That really just hit the nail on the head in regards to Edens' personality. She doesn't realise it, but she is truly such a caring and good person who just loves so deeply and purely. She will love someone to the point where she will let herself be harmed, because as long as they say they love her, or she assumes that they do, she would let them do anything to her.
I can honestly say I truly didn't know who was going to survive till the end. Usually in mystery/horror books I can get a good guess and suss out the plot, and while I did get a few things right to my great enjoyment the ending was still one I didn't see coming.
A great sapphic thriller book rec, I recommend this one and I am definitely going to check out Kate Alice Marshalls' other books. 
Also. I just want to say that Eden having a crush on that one teacher was so relatable.